Allanblackia floribunda Oliv.

Transcription

1 Allanblackia floribunda Oliv. Protologue Fl. trop. Afr. 1: 163 (1868). Family Clusiaceae (Guttiferae) Vernacular names Vegetable tallow tree (En). Bouandjo, ouotéra (Fr). Kionzo (Po). Origin and geographic distribution Allanblackia floribunda occurs in the rainforest zone from Nigeria east to the Central African Republic and eastern DR Congo, and south to northern Angola; there is one old herbarium specimen collected in Benin. Uses The fat obtained from the seed, known as allanblackia fat or beurre de bouandjo in Congo, is used in food preparation. Recently, the international food industry has become interested in the fat as a natural solid component for margarines and similar products. The seeds are eaten in times of food scarcity and are also used as bait in traps for small game. The fruit s slimy pulp can be made into jams and jellies. The wood is locally used, but is of secondary importance. In Nigeria it is used in construction of local houses. Twigs have been used as candlesticks. In Gabon a decoction of the inner bark is taken to treat dysentery and as a mouthwash to treat toothache, in Congo to treat stomach-ache. In DR Congo a decoction of the bark or leaves is taken to treat asthma, bronchitis and cough. Sap squeezed from the bark is a component of a medicine used to treat urethral discharge. Small twigs are used as chew-sticks or toothpicks. Production and international trade Traditionally, the seeds and fat are marketed on a small scale in local markets, e.g. in Cameroon. Currently, an international market chain for the seed and fat of Allanblackia floribunda is being established in Nigeria. It is estimated that Nigeria produced about 50 t of allanblackia oil in The wood is nowhere important as timber, although the tree is locally common. Properties The seeds contain a fat that is solid at ambient temperatures. The kernel, which makes up about 60% of the seed, contains about 72% fat. The fatty acid composition of the fat is approximately: stearic acid 45 58% and oleic acid 40 51%. Only traces of other fatty acids are present. Its composition and relatively high melting point (35 C) makes the fat a valuable raw material that can be used without transformation to improve the consistency of margarines, cocoa butter substitutes and similar products. The fairly hard heartwood of Allanblackia floribunda is pale red or brown and usually fairly distinctly demarcated from the thick, pinkish beige sapwood. The grain is fairly straight, texture medium to coarse. The wood has little lustre. The density is 860 kg/m 3 at 12% moisture content. At 12% moisture content, the modulus of rupture is 107 N/mm 2, modulus of elasticity 13,700 N/mm 2, compression parallel to grain 46 N/mm 2 and Chalais-Meudon side hardness 3.3. Dry wood saws well, but green wood may spring on conversion. It is fairly easy to work with hand and machine tools. It is fairly durable, and moderately resistant to termites. A prenylated xanthone, named allanxanthone A, has been isolated from the bark, as well

2 as 1,5-dihydroxyxanthone and 1,5,6-trihydroxy-3, 7-dimethoxyxanthone. The compounds isolated showed moderate in-vitro cytotoxicity against the KB cancer cell line. Adulterations and substitutes The fat from the seeds of Allanblackia floribunda is very similar in composition to that of Allanblackia parviflora A.Chev. and Allanblackia stuhlmannii (Engl.) Engl. Description Evergreen, dioecious, medium-sized tree up to 30 m tall; bole fairly short, straight, cylindrical, without buttresses but sometimes basally thickened; bark surface reddish brown to blackish, with small irregular scales, inner bark granular, reddish or brown, exuding a little clear sap; branches numerous, whorled, horizontal, hollow, with longitudinal grooves, brownish black, glabrous. Leaves opposite, simple and entire; stipules absent; petiole c. 1 cm long, glabrous; blade elliptical to ovate, rarely obovate, 8 25 cm 3 8 cm, base rounded or cuneate, apex acuminate, thinly leathery, glabrous and shiny, pinnately veined with numerous lateral veins. Inflorescence a terminal raceme or panicle with strongly reduced branches or flowers single or in pairs in leaf axils. Flowers unisexual, regular, 5-merous, pinkish or reddish, rarely white; pedicel 3 8 cm long; sepals orbicular, unequal, outer ones 5 8 mm in diameter, inner ones mm in diameter, glabrous; petals obovate to orbicular, mm long, glabrous; male flowers with numerous stamens in 5 bundles opposite the petals, mm long, anthers arranged on the internal face of the bundle; disk star-shaped with deeply folded glands; female flowers with superior, incompletely 5-celled ovary and sessile stigma, staminal bundles reduced to a few free, 4 5 mm long staminodes, disk glands grooved. Fruit a large ellipsoid berry cm 5 14 cm, with 5 longitudinal ridges, seeded. Seeds ovoid, cm cm, enclosed in a pinkish aril; embryo small, embedded in oily endosperm. Seedling with hypogeal germination. Other botanical information Allanblackia comprises about 10 species, and is restricted to tropical Africa. Allanblackia parviflora A.Chev. is sometimes included in Allanblackia floribunda. However, their areas of distribution are disjunct, the former occurring from Guinea and Sierra Leone to Ghana. Allanblackia gabonensis (Pellegr.) Bamps occurs in Cameroon and Gabon. The fat from its seeds, locally also called beurre de bouandjo, is used in cooking. Anatomy Wood-anatomical description (IAWA hardwood codes): Growth rings: 2: growth ring boundaries indistinct or absent. Vessels: 5: wood diffuseporous; 13: simple perforation plates; 22: intervessel pits alternate; (23: shape of alternate pits polygonal); 25: intervessel pits small (4 7 μm); (26: intervessel pits medium (7 10 μm)); 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 42: mean tangential diameter of vessel lumina μm; 43: mean tangential diameter of vessel lumina 200 μm; 46: 5 vessels per square millimetre; 47: 5 20 vessels per square millimetre; 56: tyloses common. Tracheids and fibres: 61: fibres with simple to minutely bordered pits; (63: fibre pits common in both radial and tangential walls); 66: non-septate fibres present; 70: fibres very thick-walled. Axial parenchyma: 85: axial parenchyma bands more than three cells wide; 87: axial parenchyma reticulate; (92: four (3 4) cells per parenchyma strand); 93: eight (5 8) cells per parenchyma strand; (94: over eight cells per parenchyma strand). Rays: 98: larger rays commonly 4- to 10-seriate; 102: ray height > 1 mm; 107: body ray cells procumbent

3 with mostly 2 4 rows of upright and/or square marginal cells; 108: body ray cells procumbent with over 4 rows of upright and/or square marginal cells; 115: 4 12 rays per mm. Mineral inclusions: 153: crystal sand. (E. Ebanyenle, A.A. Oteng-Amoako & P. Baas) Growth and development Under natural conditions, trees start flowering after about 12 years. Flowering occurs during a large part of the year, in particular from January to September. Fruits take nearly a year to mature and ripe fruits are also found during a large part of the year. The fruits are eaten by wild pigs and porcupines, which may distribute the seeds. Ecology Allanblackia floribunda is a common understorey tree of lowland closed evergreen rainforest and riverine forest, and also in secondary and swamp forest, up to 1000 m altitude. It is common on strongly leached, acid soils with ph Estimates in Cameroon indicate that in very wet forest, densities of trees with a stem diameter of >10 cm are about 150 stems per km 2 ; estimates for similar areas in Nigeria are about 250 stems per km 2. Propagation and planting Seeds are recalcitrant. Germination takes 6 18 months and germination rates are very low. Natural regeneration is affected by seed predation and collection. The weight of 100 seeds is about 1 kg. Keeping the fruits for a few months on damp sites (covered with banana leaves and buried partially) and scarification of the seedcoat improve germination rates only slightly. Methods of propagation by cuttings and grafting are being developed. When planting vegetatively propagated material, both male and female trees should be planted. Management Efforts to domesticate Allanblackia floribunda are underway, but at present seed is only collected from wild stands or from trees retained on farm land. Trees are left on the farms when clearing the land for cultivation and managed especially for shading cocoa. Diseases and pests The fruits and seeds are eaten by many wild animals and losses are great unless mature fruits are collected frequently. There have been observations of seed borers. Harvesting The degree of maturity of fruits on the tree can not be estimated, so mature fruits are left to drop to the ground and are then collected. The harvesting season is long (from January to April) and in some places peaks coincide with labour demands on the farm or with the harvest season of other forest products. For individual groups of trees the fruiting season is shorter and preliminary work indicates that collection of fruits from wild stands can be economical. Handling after harvest Fruits are stored under a cover of leaves to allow the fruit pulp to disintegrate. To extract the seeds, fruits are crushed between the hands and seeds are rubbed clean. For oil extraction, the seeds are dried well before they are taken to the buying centres, where trained personnel check the moisture content and weight, after which the seeds are ready for storage in gunny bags. To extract the fat, seeds are dried and crushed; the resulting mass is mixed with water and boiled until the fat separates and floats to the surface, from where it is scooped off. More modern hydraulic and screw press equipment is now also

4 used. Genetic resources Allanblackia floribunda occurs in a vast area and although rainforest areas are decreasing, it is not considered vulnerable. Collection of the seeds and wildlings may locally influence the natural regeneration. Breeding Selection of high-yielding trees for seed collection and vegetative multiplication has started recently. Selection criteria include seed and fruit size and abundance, and tree size and structure. Prospects If domestication efforts are successful, Allanblackia floribunda or one of the related large-fruited Allanblackia species may become a promising crop in the rainforest zone of Africa. Collection of seed from wild stands is possible, but its economical viability is poor, except possibly in areas where Allanblackia floribunda is most common. Major references Bamps, P., Notes sur les Guttiferae d Afrique tropicale 4: Revision du genre Allanblackia Oliv. Bulletin du Jardin Botanique National de Belgique 39: Bamps, P., Guttiferae (Clusiaceae). In: Boutique, R. (Editor). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Jardin botanique national de Belgique, Brussels, Belgium. 74 pp. Eyog Matig, O., Ndoye, O., Kengue, J. & Awono, A. (Editors), Les fruitiers forestiers comestibles du Cameroun. IPGRI Regional Office for West and Central Africa, Cotonou, Benin. 204 pp. Takahashi, A., Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp. World Agroforestry Centre, undated. Agroforestree Database. [Internet] World Agroforestry Centre (ICRAF), Nairobi, Kenya. Sites/TreeDBS/ aft.asp. Accessed January Other references Bolza, E. & Keating, W.G., African timbers: the properties, uses and characteristics of 700 species. Division of Building Research, CSIRO, Melbourne, Australia. 710 pp. Heckel, E., Les graines grasses nouvelles ou peu connues des colonies françaises. Challamel, Paris, France. 187 pp. Hendrickx, H., Project Novella: A pro-profit public-private partnership in a framework of environmental and social benefits. [Internet] Unilever, Vlaardingen, Netherlands. 24 pp. nederlands/leden/partners/werkgroepen/bossen/documenten/ %20Unilever%20presentation.pdf. Accessed March InsideWood, undated. [Internet] Accessed May Menninger, A.D., Edible nuts of the world. Horticultural Books, Stuart FL, United States. 175 pp. Nkengfak, A.E., Azebaze, G.A., Vardamides, J.C., Fomum, Z.T. & van Heerden, F.R., A prenylated xanthone from Allanblackia floribunda. Phytochemistry 60: Normand, D. & Paquis, J., Manuel d identification des bois commerciaux. Tome

5 2. Afrique guinéo-congolaise. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 335 pp. van Rompaey, R., Distribution and ecology of Allanblackia spp. (Clusiaceae) in African rain forests. [Internet] Report to Unilever Research Laboratories, Vlaardingen. nederlands/leden/partners/werkgroepen/bossen/documenten/ %20Distibution%20and%20ecology%20of%20Allanblackia%20spp%20(Clusiac eae)%20in%20african%20rain%20forests.pdf. Accessed November Vivien, J. & Faure, J.J., Fruitiers sauvages du Cameroun. Fruits Paris 43(10): Wilks, C. & Issembé, Y., Les arbres de la Guinée Equatoriale: Guide pratique d identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp. Sources of illustration Thonner, F., The flowering plants of Africa. An analytical key to the genera of African phanerogams. Dulan & Co., London, United Kingdom. 647 pp. Wilks, C. & Issembé, Y., Les arbres de la Guinée Equatoriale: Guide pratique d identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp. Author(s) C. Orwa World Agroforestry Centre (ICRAF), United Nations Avenue, Gigiri, P.O. Box GPO, Nairobi, Kenya M. Munjuga World Agroforestry Centre (ICRAF), United Nations Avenue, Gigiri, P.O. Box GPO, Nairobi, Kenya Editors H.A.M. van der Vossen Steenuil 18, 1606 CA Venhuizen, Netherlands G.S. Mkamilo Naliendele Agricultural Research Institute, P.O. Box 509, Mtwara, Tanzania General editors R.H.M.J. Lemmens PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands L.P.A. Oyen PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands Photo editor A. de Ruijter PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands Correct citation of this article:

6 Orwa, C. & Munjuga, M., Allanblackia floribunda Oliv. [Internet] Record from Protabase. van der Vossen, H.A.M. & Mkamilo, G.S. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l Afrique tropicale), Wageningen, Netherlands. < Accessed 11 January 2010.